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Module:User:Mr. Stradivarius/League table

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--                                                                                    --
--                                   LEAGUE TABLE                                     --
--                                                                                    --
--  This module generates league table templates for various sports.                  --
--                                                                                    --
----------------------------------------------------------------------------------------

local html_builder = require('Module:HtmlBuilder')
local lang = mw.language.getContentLanguage()

----------------------------------------------------------------------------------------
-- Team class
-- 
-- The team class deals with all the data about a particular team in the league table.
----------------------------------------------------------------------------------------

local team = {}

-- Fields whose initial value should be 0.
team.stat_fields = {
	played          = true,
	wins            = true,
	draws           = true,
	losses          = true,
	goals_for       = true,
	goals_against   = true,
	goal_difference = true,
	points          = true
}

-- Fields whose initial value should be nil.
team.other_fields = {
	name     = true,
	article  = true,
	link     = true,
	position = true
}

team.__index = function (t, k)
	if team[k] then
		return team[k]
	else
		-- Make automatic setters and getters for function calls to nonexistent functions.
		local setget, setgetkey = k:match('^([sg]et)_(.+)$')
		if setget and setgetkey then
			if not team.stat_fields[setgetkey] and not team.other_fields[setgetkey] then
				return -- Not a recognised field, so exit. We don't want people calling team:set_set_points(), for example.
			end
			if setget == 'set' then
				return function (t, val)
					t[setgetkey] = val
				end
			elseif setget == 'get' then
				return function (t)
					return t[setgetkey]
				end
			end
		end
	end
end

function team.new(display)
	local obj = {}
	-- Set display data.
	obj.display = type(display) == 'table' and display or {}
	-- Set initial stat values.
	for field in pairs(team.stat_fields) do
		obj[field] = 0
	end
	setmetatable(obj, team)
	return obj
end

function team:set_article(s)
	self.article = s or self.name
end

function team:set_link(s)
	if s then
		self.link = s
	elseif self.article == self.name then
		self.link = mw.ustring.format('[[%s]]', self.name)
	else
		self.link = mw.ustring.format('[[%s|%s]]', self.article, self.name)
	end
end

function team:set_played(n)
	if n then
		self.played = n
	else
		self.played = self.wins + self.draws + self.losses
	end
end

function team:set_goal_difference(n)
	if n then
		self.goal_difference = n
	else
		self.goal_difference = self.goals_for - self.goals_against
	end
end

function team:set_points(n)
	if n then
		self.points = n
	else
		self.points = self.wins * 3 + self.draws
	end
end

function team:export()
	local row = html_builder.create('tr')
	for _, field in ipairs(self.display) do
		row
			.tag('td')
			.wikitext(self['get_' .. field](self))
	end
	return tostring(row)
end

----------------------------------------------------------------------------------------
-- league_table class
-- 
-- The leauge_table class defines the behaviour of the league table - how teams are ranked,
-- how many entries are displayed, and outputs the final wikicode.
----------------------------------------------------------------------------------------

local league_table = {}
league_table.__index = league_table

function league_table.new()
	local obj = {}
	obj.teams = {}
	
	-- We need:
	-- 1. A table of input for each team object. {wins = 2, draws = 5, name = "Arsenal"} etc.
	-- 2. A table of the data fields to be used in the league table. {wins = true, draws = true, name = true} etc.
	-- This may be different from the team input as that is typically provided by the end user.
	-- 3. A table of formatting options. Table style and class, any rows to be coloured, etc.
	
	setmetatable(obj, league_table)
	return obj
end

function league_table:add_team(obj)
	table.insert(self.teams, obj)
end

function league_table:sort()
	-- Sort the table first by points, then by goal difference, then in alphabetical order.
	table.sort(self.teams, function (a, b)
		local a_points = a:get_points()
		local b_points = b:get_points()
		if a_points and b_points and a_points > b_points then
			return true
		elseif a_points and a_points == b_points then
			local agd = a:get_goal_difference()
			local bgd = b:get_goal_difference()
			if agd and bgd and agd > bgd then
				return true
			elseif agd and agd == bgd then
				local a_name = a:get_name()
				local b_name = b:get_name()
				if a_name and b_name then
					return a_name < b_name
				end
			end
		end
		return false
	end)
	-- If any of the teams specified their position explicitly, use that instead.
	local positions = {}
	for i, team in ipairs(self.teams) do
		local pos = team:get_position()
		if pos then
			table.insert(positions, {old_pos = i, new_pos = pos})
		end
	end
	for _, pos_table in ipairs(positions) do
		local obj = table.remove(self.teams, pos_table[old_pos])
		table.insert(self.teams, obj, pos_table[new_pos])
	end
	-- Now that we have sorted the table, set the position explicitly for all the teams.
	-- This makes it easier to deal with the team table after it has been cropped.
	for i, team_obj in ipairs(self.teams) do
		team_obj:set_position(i)
	end
end

function league_table:crop(name, pos, limit, align, more_down)
	-- This limits the output of the league table to a set of contiguous entries centered around a team or a position.
	-- name: the name of the team. This is used to find the position if specified.
	-- pos: the position. Used for the position if no name was specified.
	-- limit: the number of entries to limit the table output to. Defaults to 3, or 2 if we are at the top or bottom of the table.
	-- align: whether the specified position appears at the top, bottom or middle of the selection. It is at the center by default.
	-- more_down: if the selection is center-aligned and an even number of entries are specified, display more down entries than up if this is true.
	-- This method should be called after the league table has been sorted.
	local team_count = #self.teams
	if team_count <= 1 then return end -- If there is only one team, then we don't need to do any calculation.
	if name then
		for i, obj in ipairs(self.teams) do
			local obj_name = obj:get_name()
			if name == obj_name then
				pos = i
			end
		end
	end
	if not pos then return end
	if not limit then
		if pos == 1 or pos == team_count then
			limit = 2
		else
			limit = 3
		end
	end
	if limit >= team_count then return end -- If the limit is higher than the team count then we just use the whole table.
	local start, finish
	if align == 'top' then -- 'Top' means that the position is at a lower index than all the other entries, as the top team has position 1 in the league table.
		finish = pos + limit - 1
		if finish > team_count then
			finish = team_count
		end
		start = finish - limit + 1
	elseif align == 'bottom' then -- 'Bottom' means that the position is at a higher index than all the other entries.
		start = pos - limit + 1
		if start < 1 then
			start = 1
		end
		finish = start + limit - 1
	else
		-- Assume align == 'center'.
		local limit_mod2 = limit % 2
		local limit_div2 = math.floor(limit / 2)
		local ideal_start, ideal_finish -- Where the table would start and finish if we weren't limited by the start and end of the table itself.
		if limit_mod2 == 1 then
			-- Odd number, more_down doesn't matter.
			ideal_start = pos - limit_div2
			ideal_finish = pos + limit_div2
		elseif more_down then
			-- Even number with more down than up. Down in this case means a higher index, as the top team has position 1 in the league table.
			ideal_start = pos - limit_div2 + 1
			ideal_finish = pos + limit_div2
		else
			-- Even number with more up than down. Up means a lower index number.
			ideal_start = pos - limit_div2
			ideal_finish = pos + limit_div2 - 1
		end
		if ideal_start < 1 then
			start = 1
			finish = start + limit - 1
		elseif ideal_finish > team_count then
			finish = team_count
			start = finish - limit + 1
		else
			start = ideal_start
			finish = ideal_finish
		end
	end
	local ret = {}
	for i = start, finish do
		table.insert(ret, self.teams[i])
	end
	self.teams = ret
end

function league_table:export()
	local root = html_builder.create('table')
	root
		.addClass('wikitable')
	for _, team_obj in ipairs(self.teams) do
		root
			.wikitext(team_obj:export())
	end
	return tostring(root)
end

----------------------------------------------------------------------------------------
-- Process arguments from #invoke and define the main module structure.
----------------------------------------------------------------------------------------

local p = {}

local function getArgNums(prefix, args)
	-- Returns an array containing the numbers of arguments with a given prefix.
	local nums = {}
	for k in pairs(args) do
		if type(k) == 'string' then
			local num = mw.ustring.match(k, '^' .. prefix .. '([1-9][0-9]*)$')
			num = tonumber(num)
			if num then
				table.insert(nums, num)
			end
		end
	end
	table.sort(nums)
	return nums
end

function p._main(args)
	local output_table = league_table:new(args)
	return output_table:export()
end

function p.main(frame)
	-- If called via #invoke, use the args passed into the invoking template, or the args passed to #invoke if any exist.
	-- Otherwise assume args are being passed directly in from the debug console or from another Lua module.
	local origArgs
	if frame == mw.getCurrentFrame() then
		origArgs = frame:getParent().args
		for k, v in pairs(frame.args) do
			origArgs = frame.args
			break
		end
	else
		origArgs = frame
	end
	-- Trim whitespace and remove blank arguments.
	local args = {}
	for k, v in pairs(origArgs) do
		if type(v) == 'string' then
			v = mw.text.trim(v)
		end
		if v ~= '' then
			args[k] = v
		end
	end
	return p._main(args)
end

----------------------------------------------------------------------------------------
-- Testing area
----------------------------------------------------------------------------------------

local dts = require('Module:User:Anomie/deepToString').deepToString

function p.test()
	local display = {'played', 'goal_difference', 'points'}
	local team1 = team.new(display)
	team1:set_name('Team 1')
	team1:set_points(6)
	team1:set_goal_difference(15)
	local team2 = team.new(display)
	team2:set_name('Team 2')
	team2:set_points(20)
	team2:set_goal_difference(15)
	local team3 = team.new(display)
	team3:set_name('Team 3')
	team3:set_points(2)
	team3:set_goal_difference(3)
	local team4 = team.new(display)
	team4:set_name('Team 4')
	team4:set_points(20)
	team4:set_goal_difference(40)
	local team5 = team.new(display)
	team5:set_name('Team 5')
	team5:set_points(15)
	team5:set_goal_difference(30)
	local team6 = team.new(display)
	team6:set_name('Team 6')
	team6:set_points(8)
	team6:set_goal_difference(-15)
	local team7 = team.new(display)
	team7:set_name('Team 7')
	team7:set_points(3)
	team7:set_goal_difference(-15)
	local team8 = team.new(display)
	team8:set_name('Team 8')
	team8:set_points(20)
	team8:set_goal_difference(40)
	local mytable = league_table.new()
	mytable:add_team(team1)
	mytable:add_team(team2)
	mytable:add_team(team3)
	mytable:add_team(team4)
	mytable:add_team(team5)
	mytable:add_team(team6)
	mytable:add_team(team7)
	mytable:add_team(team8)
	mytable:sort()
	mytable:crop('Team 6', nil, 4, nil, false)
	return mytable:export()
end

return p